White pine for lapstrake

[Mustanger]

I will soon build a wooden dory, Swampscott type, open rowing/sailing, traditional lapstrake, exact model not decided yet. Too much information! Selecting lumber for the sawn frames and for the planks is my challenge for this thread. There is a lot of luan in use in Texas. I may use it for framing. I think white pine for strakes will be fine. Where to get "white pine"? Later, we will look at fasteners and some other details.

[Guest20100203]

The Swampscott dory is the Cadillac of the dory form, not to be confused with it's lesser cousins, such as the Grand Banks. In it's true form, it is essentially a round bilge boat, with enough bottom flat to take to a beach or grounding upright. These are fine sea boats and handle well, but their low initial stability can rattle a sailor not accustomed to the quickness of their roll period. This can be quite alarming to the modern skipper, so many of the Swampscott's seen today are modified, some what, to "calm them down". This generally means a wider bottom and other slight changes to increase the craft's stiffness, if done correctly, this doesn't affect the boat's abilities.

The traditional Swampscott had a double bottom, with the outer layer being sacrificial and replaced when necessary. They also had four strakes per side, but with plank widths needed in a boat of this size, particularly the garboards, being all but attainable, the modified versions usually call for 5 strakes, permitting the garboard to be gotten from 12" stock.

In the eastern part of the US, northern white pine or cedar is typically called for in the planking specs. A few knots, if not very big, well scattered and solid through, can be acceptable in the planking stock. Atlantic white cedar is good stuff, but difficult to find. Eastern white pine or more commonly called number 2 common construction grade pine can be used with careful use of scarfs and splices. This stuff is has resinous pockets and knots that need to be sealed before it can be finished. The great majority of strength is gotten from the lap construction, so good fits and fasteners are a must.

There are many versions of Swampscott dory plans available. I have a 16' and 17' traditional Swampscott, a 16' modified, a 19' double ended surf boat (closer to a Chamberlain dory) and a few other pulling boats that may be of interest to you. If you'd drop me an email (click on my icon), we can discuss the details. I also have glued lapstrake models.

[Guillermo]

Originally Posted by PAR

..but their low initial stability can rattle a sailor not accustomed to the quickness of their roll period...

PAR,
There seems to be some contradiction in your words, as low initial stability leads to slow rolling, rather than quick. Maybe the 'quickness' you mention is rather due to the high sensitivity of this boat to lateral shifting of weights and the induced rapid lateral movements a not used persoan makes to keep the boat upright...?

I've never sailed a Swampscott dory, but I when I was a boy I used to go fishing in a Taylor 470, which very much resembles the Swampscott dory, although with a higher bow. And, yes, it was a tippy boat also.

Some interesting photos:
http://www.geocities.com/garylambda/Stability.html

[Guest20100203]

'Ya got me, they are quick about their moment, quite tender, but this is what makes them fast sailors and excellent under oar. They do firm up, but most, unfamiliar with the qualities of the boat, are very uncomfortable at that point. A quick look at their sections explains much. I must learn to proof read.

[Mustanger]

There are a half-dozen ways to build these dory frames. Grown frames are not an option for this first boat. Using some form of cleat or gusset, wood or metal, apparently worked well for countless boats in the past. I need to decide which method I want to use. How well do these cleated/gusseted frames hold up? How stiff are they after a couple of years? Will sawn and cleated frames with good lap strakes maintain the shape without fixed thwarts, mast partners, decks, or coamings, to connect the sheers? I have no experience to apply to these details. Another method is lamination. I am considering laminating one-piece frames using strips of Philippine Mahogany (luan?). Given the sections for a Swampscott dory, is this something you personally would attempt? I have read that PM responds to steaming.

[Guest20100203]

Mustanger, you truly need a set of plans to work from. They not only provide a set of lines from which the boat shapes can be picked up, but most importantly the details of it's construction. It's real easy to over build a dory and destroy it abilities. Most folks don't build to light, but it happens too. Most open craft usually require athwartship stiffeners to keep them from folding up, though some designs can tolerate not having thwarts. Much depends on the engineering concepts employed in the design. You'd be well advised to search for a set of plans, then build to the plans with minimal changes.

[Mustanger]

PAR, I value your advice, having read a number of your posts. I have invested many an hour reading "The Dory Book" and "Building Classic Small Craft -- Volume 1" by John Gardner and studying his plans and methods. I own a copy of "Skiffs and Schooners" and have a library book "The Complete Design Catalog -- Pete Culler's Boats" and have rigorously studied his plans and methods. I have a copy of Howard Chapelle "Complete Handbook of Wooden Boatbuilding" and have studied his plans and methods. Right now I have Volume 1 and 2 of Walter Simmons "Lapstrake Boatbuilding". And of course I have burned up the Internet. I could build my dory straight from "The Dory Book". There will be a plan lofted full size on the floor. Now, every source is a little different. So I ask real people what they think or what they have experienced. I am hung on three items. Building frames is one. Example: John Gardner proposes galvanized steel or bronze clips for gussets. Ain't no way. My question to you (guys) was how do these methods work in the real world. What method would you use for a "traditional" wooden craft which will definitely have Epoxy in it and maybe a plywood garboard? I have never seen one of these craft, not one of any description. Dory, wherry, peapod, sawn frames, bent frames, oak, cedar, spruce, whitepineelmlocustapplegrownframes. My question about laminated frames was not too far out there considering what I've seen in these and many other pages. You have the common sense and experience -- I have the books and no boat. And an open mind.

[Guest20100203]

All of the framing methods can work well. From an engineering stand point the fundamentals are similar in their application, but the principles and techniques may differ greatly.

Sawn frames with gussets works very well as do bent or laminated. A gusseted frame's success can be directly related to the sizing of the gussets. It's difficult to speak in generalities on each methods (there are dozens) all having good and bad points to consider. Eventually you'll have to select a dory style (model) and a construction type, then engineer the structure's scantlings to withstand the tasks you expect it to tolerate. There are a number of guidelines that can help this process a bit, but each has to be weighed on it's merit. An example would be scaling down planking thickness from a solid lumber plank to one using plywood. Another would be increasing frame spacing or decreasing dimensions for use with a stronger planking material. These guides are very general in nature, but can help keep the boat light enough to perform well.

The steel clips John Gardner employed work very well and because of their strength, can be quite small, compared to a solid lumber gusset. I like metal gussets, but only in larger craft.

Bent frames have the advantage of being very light. Laminated frames aren't quite as light as bent, but are more stable. Sawn frames take up a lot more interior volume then bent or laminated and are heavier, but are much easier to build. Do you see what's happening? All elements of yacht design are a series of compromises. The shape of the keel to how you attach the stays to the masthead and everything in between are compromises, necessary to fill as closely as possible, the design requirements. Some boats have few, because there may be only a couple of things to consider (like an all out racer), but most boats try to fit many roles and must sacrifice in some areas to the benefit of others.

In a home built design, this becomes very difficult for the designer. Most are forced to over design, knowing the backyard builder will not use the best materials or techniques during construction. This produces a boat that is heavier then it needs to be, effecting many other aspects of the design.

Since you know your skills, tools, materials available, etc. you have a decided advantage over the average guy who buys a set of plans. You can build closer to the edge, saving materials, time, money and increasing performance and economy.

Plywood garboards are a common upgrade from solid lumber, if the design can handle it. I just installed some plywood garboards on a 26' cruiser, replacing 3 edge glued planks per side, with one continuous plywood garboard (epoxy scarfs). This upgrade will make the boat tighter, stronger, the bottom will take more abuse and the structure will move less underway. Not all designs can have this, being a judgment call from experience with others of the same type.

Do you have a style of dory you want to build? Set of plans? Designed by who and what changes do you want to incorporate? You know I'm going to ask why, so include this as well. From there we can formulate a design brief and figure out what areas of the design can be fooled with and what shouldn't, of course all considering your skills, materials availability, etc. If interested in something more complex, then drop me an email and we can go over your wishes.

I would be interesting to see this dory developed on line. Then again you may just get fed up with the lot of us and build one of your own choosing.

[Mustanger]

PAR -- If I had to choose today, I would select the modified Swampscott dory in John Gardner's "Building Classic Small Craft" Volume 1. The lines and offsets are complete. There is a whole chapter of details, including the sprit rig. There are four methods and three materials for frames, including this: "It is even possible to laminate continuous one-piece frames from thin strips glued on a form". Two methods and three materials for the stem and the transom. Or is it three and two? Plywood bottom or solid wood, two layers. It doesn't mention plywood garboard, but why not? Most of the other 7 dory plans mention it. There are so many options, I don't need to invent any more. I realized what my problem was with sawn/gusseted frames. I picture those things being pulled outward and squeezed inward incessantly by apes or mules intent on destroying them. I picture the wood grain splitting at the fasteners. I see this perfect craft becoming a twisted mess after a couple years' use. I see now that it probably ain't true.
I would like to see a set of real plans, by other builders, that come in a package, not in a book. I have no problem buying a set of plans. But I do not want to spend hundreds of planking dollars speculating on plans just to take a look. So now we can discuss the plans that you own.
Thanks for all your help, man.

[Guest20100203]

John Gardner's modified Swampscott is an excellent example of the smaller sailing dories. The plans shown in volume one are almost complete. He did another similar version of this dory in the second volume of "Building Classic Small Craft". Between the two sets of his plans you should have a very good idea of how to construct this dory. The second version is the better of the two for all around utility (sailing, rowing and use with a small kicker), though version one will row slightly better and be faster under sail, if sailed with a crew willing to hold her down by hiking.

What type of build do you want, traditional, modified traditional, modern? Some of the newer designs incorporate epoxy glued seams rather then clenches or roves. The result is a boat that doesn't have frames (or very few) and is exceptionally water tight which can't be said of the traditional types.

I'm an experienced builder and need only the offsets and a general design brief (construction details, frame spacing, etc.) to complete a boat. Most backyard builders require a very complete set of plans and lengthy instructions with many details to have a chance at finishing the project.

Some firms, like Glen-L and Clark Craft, specialize in selling plans for the amateur. These plans are complete and come with some instructions, many thousand being built world wide. A number of these designs also have frame kits, covering or fastener kits available too. They sell lots of plans, so the price is quite low. For the average guy, these plans are my recommendation as they'll get the idea and maybe finish the boat.

I suspect you are a little different then the average guy looking to build, the choice of a Swampscott, suggests this. Versions of the Swampscott can be had from Glen-l for about 50 bucks, though it looks to be more like a Grand Banks then a Swampscott. Personally I recommend the 18' dory from WoodenBoat seen at http://www.woodenboatstore.com/prodi...number=400-081 It's very difficult to compete with that price and the plans are very good. Iain Oughtred designed this fine example and she can be build over sawn frames or traditionally. It also can be built as glued lap plywood planking. I have to admit I can't compete with the designers that have the eye of WoodenBoat Magazine (Iain Oughtred) editors. He certainly is a favorite of theirs, justly so, he does nice work. One of these days, I'll get a review from Mike O'Brien (their senior editor) and my plans sales will go through the roof (and my prices can come down) I have appeared in the magazine seven times, but none featured me.

If you're a reasonably bright guy, you should have little trouble following the plans by John Gardner. They'll be some head scratching, but it's a pretty simple boat. Stick to the recommendations of the plans, as small boats are very weight sensitive and alterations can screw up a nice design pretty easily.

For the record, I have several dory plans, a few traditional, but most glued lapstrake or tape and seam (smooth sided) and my prices are in the 200 dollar range for a basic set, no full size patterns, which would cost me 200 bucks just to print out. WoodenBoat sells a few plans a month for Iain, so he can afford to print off several sets at once (which is much cheaper) One of these days I'm going to buy a big old plotter (when I have a few grand laying around without a label on it) and start printing my own full size patterns, but until then I'll have to rely on the local architectural drafting shop to do it for me.

[Mustanger]

PAR -- I intend to use the plan in Gardner's book pretty much to the letter. The plan will be lofted full size on the floor. Laps will be clenched with copper rivets, wood to wood. I want to stay away from tapes and resins for waterproofing purposes. White oak will probably be the framing material, and it can be procured off the shelf. Material availability will decide the planking wood. I'm liking white cedar or Alaskan yellow cedar. Neither of those is on the shelf around here. White pine? I could probably go to San Antonio or Houston and hand select a good grade. Having read about flitches I want to pursue that avenue, see if it is the best way. Seems like slab sawn would be the best cut for a plank that has rows of fasteners down its length. I have studied wood so much this week, now I want to cut and mill my own. Buy a truck, a portable saw mill, and travel the country cutting planking material. Wouldn't leave much time for boat building or living-making, but it would be a fascinating activity. Anyway, you know what they say: "The hardest part of building a boat is getting started".